I want to catch articuno so I searched it up and found out you can find it in the cliff world ( red wormhole) when I went there I encountered zapdos and moltres first then a cresselia.
My question is can this happen ?
Shouldn’t articuno come after molters ?
No, most legendary trios don't come in order. However, there are a few exceptions. For example, in order to get Giratina, you need both Dialga and Palkia. This isn't an order as those pokémon are version exclusive, but it makes Giratina have to be caught last. However, there really isn't an order as they are caught in different wormholes. So, there isn't an order, but some Pokémon require the other 2 in their trio to be caught first.